Improvement in collecting waste lead fumes



G. T. LEWIS. Collecting Waste-Lead'Fume.

No. 212,855. Patented Mar.4,1879.

Afsz s 3 lhVenl or N. PETERS. PHOTO-LITHQGRAPHER, WASHINGTON n C UNITEDSTATESPATENT OFIE.

GEORGE T. LEWIS, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN COLLECTING WASTE LEAD FUMES.

Specification forming part of Letters Patent No. 212,855, dated March 4,1879; application filed October 22, 1878. c

To all whom it may concern:

Be it known that I, GEORGE T. LEWIS, of the city and county ofPhiladelphia, in the State of Pennsylvania, have invented a new anduseful improvement for collecting waste fumes which incidentally andnecessarily escape in the furnaces used for smelting lead ores, of whichthe following is a specification:

In the process of smelting lead ores large amounts'of volatile fumesnecessarily escape and are lost. These escaping fumes are also found tobe injurious to the surrounding land.

Various attempts have been heretofore made, by passing these escapingfumes through horizontal or ascending flues of great length, to causethe fumes to be deposited; but these were attended with great expense,and were only partially successful.

I have discovered that by passing the escaping fumes from alead-ore-smelting furnace through a series of cooling-tubes, and theninto a series of bagging, the escaping fumes can be thoroughly andeffectually strained out and collected, while the attachment of thecooling-tubes and collecting-bags does not interfere with the smeltingoperations.

This cooling and collecting apparatus may be used in combination witheither of the ordinary lead-ore smelting or reducing furnaces, such asthe Scotch-eye furnace, the reverberatory smelting-furnace, or thecupola smeltingfurnace, or with the lead-refining furnaces.

In the accompanying drawing I show the apparatus as combined with thestack of a Scotch-eye reducing-furnace, although it may be combined inlike manner with the stack of either of the equivalent furnacesmentioned above.

The drawing represents an ordinary Scotcheye lead-smelting furnace.

B is the furnace proper, in which the lead ore, in admixture withcarbon, is reduced. X is the furnace stack or chimney, through which thefumes ascend. This ascending fine is common to each of thesmelting-furnaces or refining-furnaces above mentioned.

A descending flue, A, leads from this stack to the commencement of aseries of vertical cooling-tubes, A A A A A, so arranged that the fumesare forced to ascend and descend successively as they pass along throughthe tubes. These tubes are made of sheet metal, as thin metal rapidlythrows off the heat of the contents and cools the fumes. These tubesshould be about two feet in diameter, and the series should furnishabout three hundred and fifty feet of aggregate length. These verticaltubes can be cleaned out by openings with movable covers made in thelower part of the flue, if necessary; but the deposit will be verysmall. The last tube of the series of tubes communicates with the eye ofa fan, H. The fumes are drawn by this fan H through the series ofcooling-tubes and discharged into a tube, K, which connects with ahorizontal tube, L. From this tube L are suspended a series of strainersor bags, M M M, composed of textile fabric, through the meshes of whichthe gases escape, leaving the solid material or fume proper within thebag or strainer. Equivalent straining material for textile fabric may beused. These fumes, so collected, are composed of sulphate,'sulphite,carbonate, and oxide of lead when ordinary galena ore is smelted, or,when carbonate lead ores are smelted, the fumes collected will be foundto consist mainly of oxide and carbonate of lead. If the ores smeltedare the argentiferous ores of lead, then the fumes so collectcd willcontain, in addition to the above-mentioned salts of lead, also thecorresponding salts of silver.

The fumes when collected in the bags are removed therefrom by shaking,and may be either used as a gray pigment direct, or, after purification,as a whiter pigment; or these fumes may be returned to the furnace andreworked for the metals which they contain.

I am aware that it has been heretofore attempted to collect the wastefumes of leadsmelting furnaces in long lines; but this was expensive andunsatisfactory.

I am also aware that a patent was heretofore granted for blowingpulverized argentif erous ores of lead into a furnace, and then passingthe fumes through a showering-charm her to throw down the silver, andafterward the lead fumes were collected in bags; but the water employedto wash the fumes absorbed the sulphuric acid and the vapor destroyedthe bags.

I am also aware that textile fabrics have been employed With compoundreducing and oxidizing zinc-furnaces, and also with compound reducingand oxidizing lead-furnaces; but no one has combined a series ofcoolingtubes and collecting textile fabric with the lead smelting andrefining furnace so as to prevent the Waste incident to the processes ofsmelting or refining.

My present improvement consists in the direct combination, with thestack of a lead-oresmelting furnace or lead-refining furnace, of aseries of metallic cooling-tubes and a series of bags of textile fabricor their equivalent.

Having thus described my invention, What I claim, and desire to secureby Letters Patent of the United States, is-

1. In combination with the stack of a leadore-smeltingfurnace orlead-refining furnace, a cooling flue or tubing and textile bags orstraining-receptacles for collecting the escaping lead fumes.

2. The combination, with the stack of the ordinary lead-ore-smeltiugfurnace or lead-refining furnaces, of a series of cooling-tubes, ablower, and a series of bags composed of teX tile or straining fabrics,substantially as described.

GEURGE T. LEWIS.

Witnesses:

lt.- S. CHILD, Jr., SAMUEL VVETHERILL, Jr.

